A ferrule defined by Japanese Industrial Standard (hereafter, JIS) C 5981 (F12 type multicore optical fiber connector: MT connector) is known as a ferrule made of resin that is a pin engaging positioning method having guide pins on both side of a plurality of horizontally aligned optical fiber holes. With this type of ferrule, opposing contact endfaces of the ferrules are contacted against each other, to make the optical fiber endfaces of the contact endfaces be physically connected (physically contacted) to each other. With JIS C 5982 (F13 type multicore optical fiber connector: MPO connector), contact endfaces of ferrules are polished obliquely. For example, in PTL 1, FIG. 6, there is disclosed a ferrule with a contact endface that has been polished obliquely. When the contact endface of the ferrule is polished obliquely, an endface of an optical fiber is also polished obliquely, and the characteristic of a reflecting attenuation amount increases.
In PTL 2, there is disclosed that an axial displacement of optical fibers occurs when contact endfaces polished obliquely are contacted against each other. To suppress increase of optical loss due to such displacement in optical axis, forming a collimate lens in a ferrule is disclosed in PTL 3.